Chapter 10: Plate Tectonics

Reverse faults have ___ forces.

compression

Convergent boundaries form...

mountains, volcanoes, and deep sea trenches

What happens at an oceanic-oceanic collision?

the older/denser crust bends under the other. A deep-sea trench is formed.

Subduction

the process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle again

As a continent moves ___ the poles, its climate gets colder.

toward

The fact that the ____ rocks are located at the mid-ocean ridges is evidence for seafloor spreading.

youngest

The key to explaining sea-floor spreading is _________.

Magnetic stripes.

__________ occurs when one plate sinks beneath another plate.

Subduction

_________________ is the key to understanding Continental Drift.

The fit of the continents

Lithosphere

The outer shell of Earth that extends to a depth of 100 km.

Asthenosphere

The partially melted layer of the mantle that underlies the lithosphere.

Mesosaurus and Lystrosaurus are ____.

ancient reptiles (fossils)

Wegener noticed that mountain ranges on the continents of South America and ____ line up.

Africa

Oceanic-Continental Plate Boundary

Denser ocean crust sinks into the asthenosphere. Also known as a subduction zone. Old ocean crust gets pushed into the asthenosphere, where it is remelted and recycled

Scientists believe that differences in ____________ cause hot, plastic-like rock in the asthenosphere to rise toward Earth's surface.

Density

Reverse Fault

Form from compression forces; rock breaks from forces pushing from opposite directions; rock above a reverse fault surface is forced up and over the rock below the fault surface

Normal Fault

Form when rocks undergo tension; rock above the fault surface moves downward in relation to rock below the fault surface

Because the continents fit together so well, this means they were once a _______________________ and have slowly _____________ to their present locations.

single landmass; drifted

Lithospheric Plates

A number of rigid, but moving, pieces of the Earth's surface.

________________ is responsible for the Continental Drift hypothesis.

Alfred Wegener

Pangaea means...

All Earth

Panthalassa means...

All Sea

What happens at a continental-continental collision?

Because the two crusts are the same density, they squeeze and push the crust up to form mountains.

__________ is the idea that the continents move very slowly, over millions of years, parallel to Earth's surface.

Continental Drift

_________ is the key to explaining Plate Tectonics.

Convection Currents

Converging Boundaries

Forms when two (Crustal) Lithospheric plates come together.

Diverging Boundaries

Forms when two (Crustal) Lithospheric plates move apart.

Sliding Boundaries

Forms when two (Crustal) Lithospheric plates slide past each other.

A ________ is any preserved evidence of ancient life.

Fossil

__________ uses satellites to track the movement of plates.

GPS

The force of ____________ moves the plate downward and away from the ridge during ridge push.

Gravity

Who is responsible for the sea-floor spreading hypothesis?

Harry Hess

The crust and upper mantle are composed of ____________.

Lithosphere

The crust and upper mantle make up Earth's......

Lithosphere

Divergent boundaries form...

Mid-ocean ridges and rift valleys

Oceanic-Oceanic Plate Boundary

One of the plates is subducted (sinks) under the other

This name comes from two words meaning "all land".

Pangaea

________ is the supercontinent that Wegener suggested occurred on Earth about 300 million years ago.

Pangaea

_________ explains how plates move and cause major geologic features and events on Earth's surface.

Plate Tectonics

Continental-Continental Plate Boundary

Plates buckle and thicken, pushing the continental crust upward creating mountains

What is a boundary between two plates that are moving apart called?

Ridge

__________ moves a plate at a ridge.

Ridge Push

Strike-Slip Fault

Rocks on either side of the fault are moving past each other without much upward or downward movement; produced by shear forces pushing rocks in somewhat opposite horizontal directions

The Glomar Challenger provided support for the theory of Plate Tectonics by providing what?

Samples of older rock found far from mid-ocean ridges.

The Global Positioning System (GPS) is a network of _________ used to determine locations on Earth

Satellites

_____________ is the new crust formed at mid-ocean ridges.

Sea floor spreading

The Glomar Challenger gathered information about rocks on the.......

Seafloor

__________ forces a plate into the mantle.

Slab Pull

Seafloor Spreading

States that youngest rocks of the ocean floor are at diverging boundaries, moving outward.

Continental Drift

The theory that all continents are fragments of Pangaea now drifting apart.

Plate Tectonics

Theory of the formation and movement of the plates that cover the Earth's surface.

Deep-Ocean Trench

a canyon on the ocean floor at which the crust bends downward

Mid-Ocean Ridge

a chain of underwater mountains along which seafloor spreading occurs

Rift Valley

a deep valley on land that forms at a divergent boundary

Alfred Wegener was one of the first people to suggest that all of the ________ were joined together in the past. He called the one large continent _________.

continents; Pangaea

As a continent moves toward the ____, its climate gets warmer.

equator

Transform boundaries form...

major earthquakes

Until clues on the ___________ led to the idea of seafloor spreading, the mechanism of the continents moving, scientists would not believe Wegener's theory of continental drift.

ocean floor

The continents fit together like ______________.

puzzle pieces

Most of Wegener's scientist friends ____ his hypothesis.

rejected

Harry Hess' theory of __________ explained how ocean crust is generated and destroyed.

seafloor spreading

Strike-Slip faults have ___ forces.

shear

Wegener's support for continental drift theory (3 things)

similar fossils, similar rocks/mountain shapes, and climate change

Normal faults have ___ forces.

tension

What happens at an oceanic-continental collision?

the more dense oceanic crust sinks beneath the continental plate, forming a subduction zone.